Malignant cerebral gliomas are highly resistant to the currently employed treatment with combination of surgery, radiotherapy and chemotherapy. As opposed to conventional forms of therapy, the replacement of specific tumor suppressor and apoptotic genes is a treatment directed against the basic neoplastic mechanism. Malignant glioma represents a multiple-gene alterations disease. Thus, effective therapy should involve gene combinations rather than single-gene replacement. An efficient combination of genes should induce inhibition at several points of cell proliferation and activate the various pathways of programmed cell death. The delivery of the therapeutic genes can be attained by using adenoviruses as carrier vehicles. The first aim of this project is to design and construct recombinant adenoviral vectors, carrying either multiple tumor suppressor genes (Ad5-MSG), or apoptosis-mediating genes (Ad5-APG), or combination of both (Ad5-SAPG). The recombinant adenoviruses will be constructed after testing of the potential additive or synergistic effect of various combinations of adenoviruses carrying single tumor suppressor (p16, p53, Rb), or apoptotic genes (p53, E2F1, ICE, antisense bel-2), on growth and apoptosis of glioma cells. Subsequently, the biologic activity and analysis of the anti-cancer mechanisms of these constructs will be tested in a variety of glioma cell lines. The second aim will assess the in vivo efficacy, inhibition of tumorigenicity and toxicity of this combination gene approach in an animal model. The third aim will investigate the interactions among the exogenous genes and their relationship with other molecules involved in the regulation of tumorigenesis, tumor growth, angiogenesis, programmed cell death, and tumor invasion. This study presents an anti-cancer strategy based on gene combinations to generate cytostatic and cytotoxic actions through distinct growth inhibitory and cell death mechanisms.